Abstract
The effect of microstructure on the corrosion of heat-treated Ti-10 mass% Mn alloys was investigated by electrochemical impedance spectroscopy (EIS) in 10% NaCl solution of pH 0.5 at 97 °C. Sample of solution heat treatment (ST) had a single β phase, and samples subjected to the aging heat treatment at 600 °C had α phase precipitation in β phases. The EIS measurements showed that the corrosion resistance of the aging heat-treated samples showed lower values than ST sample, however, much higher values than pure Ti. Thus, Mn was effective to increase the corrosion resistance of Ti alloys. Laser micrographs of heat-treated samples indicated that α phase was selectively corroded and made the pit after the corrosion test. The transmission electron microscope (TEM)-energy dispersive x-ray spectrometry (EDXS) analyses showed that the Mn content was 9 mass% in the β phase and 0.7 mass% in α phase. Hence, it was understood that less-Mn α phase was selectively corroded in the corrosion test. However, as compared with pure Ti, the aging heat-treated samples showed much higher resistance against the corrosion by the 0.7 mass% Mn in α phase. Finally, it was concluded that it was possible to keep the high corrosion resistance for heat-treated Ti-10 mass% Mn alloy by controlling the microstructure of α phase.
Highlights
Titanium (Ti) alloys are widely used for structural applications, for example, in the chemical plants and the oil production industries
NC 0-3 samples exhibit higher impedance values (Rt) of 103 104 X cm[2] at lowest frequency region. These results show that all samples of alloys are passivated, and show high corrosion resistance even in a severe condition of 10% NaCl at a pH of 0.5 at 97 °C
Ti-10 mass% Mn alloys was investigated by electrochemical impedance spectroscopy (EIS) in 10% NaCl solution of pH 0.5 at 97 °C
Summary
Titanium (Ti) alloys are widely used for structural applications, for example, in the chemical plants and the oil production industries. The vast utilization of titanium and its alloys own to their excellent mechanical property and high corrosion resistance (Ref 1). In the case of alloying design, noble metals such as Pt, Pd, and Ru were used to increase the corrosion resistance. It was found that those Ti alloys had good resistance in acidic media (Ref 4-8). Such elements are rare metal, and, recently, their costs are increasing remarkably. It has been documented that alloying Ti with sufficient quantities of molybdenum (Mo) provides high corrosion resistance (Ref 9, 10). Ti-15 mass% Mo alloy was found to be a highly corrosion-resistant alloy instead of rare metal in high level acidic solution at elevated temperatures (Ref 11, 12)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
